© 2007-2017 Bob Hackett, Sander Kingsepp and Peter Cundall
15 May 1922:
Tokyo. Laid down at Ishikawajima shipyard as a WAKATAKE-Class destroyer and designated No. 22.
14 April 1923:
Launched and renumbered No. 12.
21 May 1924:
Completed. LtCdr (later Capt) Maruyama Yoshio (36) is the CO.
1 December 1925:
LtCdr Tokutomi Tadao (40) assumes command on paper. In reality, LtCdr Nakahara Tatsuhei (38)(the CO of KARUKAYA) assumes joint command of both vessels.
1 August 1928:
1 November 1929:
Lt (Vice Admiral, posthumously) Aruga Kosaku (45) assumes command.
30 November 1929:
Lt Aruga is promoted LtCdr.
1 December 1930:
Lt (RAdm posthumously) Amaya Yoshishige (47) is appointed the CO.
15 January 1934:
LtCdr (Rear Admiral, posthumously) Isohisa Isogu (48) (former CO of W-5, W-13) assumes command.
15 November 1934:
An unknown officer assumes command.
One of three Kampon boilers is removed reducing speed to 18 knots. 25mm AA guns and depth charge racks and throwers are fitted for 60 DCs. Extra ballast is added to compensate for the loss of topside weight and to increase stability. The changes increase her displacement to 910-tons.
1 April 1940:
Reclassified as a special duty patrol boat and renumbered 46.
5 March 1941:
PB-46 becomes temporary flagship of the Kure Guard Unit.
8 March 1942:
Departs Sukumo on an anti submarine sweep with armed merchant cruiser KINJOSAN MARU, minelayer NASAMI and subchaser CH-13.
14 July 1942:
At 0800, arrives at Saeki with auxiliary cruisers SAIGON and BANGKOK MARUs and patrol boats PB-34 and PB-35.
21 August 1942:
At 1930 ammunition ship NICHIRO MARU steering southwards in 30N 132-35E area sights an enemy submarine and PB-46 is ordered to proceed to the area to assist.
5 September 1942:
PB-46 and PB-31 escort tanker NISSHIN MARU No. 2 north through the Bungo Straits.
E 6 September 1942:
The escorts are detached.
16 October 1942:
PB-46 escorts transport SUWA MARU south towards Rabaul.
29 November 1942:
PB-46 departs Moji escorting the “D” convoy (No. 8 Military Movement) consisting of KURAMASAN and KENKOKU MARUs.
30 November 1942:
Arrives at Saeki. Later that day, the convoy departs with minelayer NATSUSHIMA as an additional escort.
E 1 December 1942:
At 29N, the two escorts are detached.
7 December 1942:
PB-46 joins aircraft transport FUJIKAWA MARU off Fukajima and escorts her south.
E 8 December 1942:
PB-46 is detached S of the Bungo Straits.
9 December 1942:
PB-46 and subchasers CH-37 and CH-39 depart Saeki escorting the “G" convoy (No. 8 Military Movement) consisting of MOMOYAMA, HOEISAN, KOSO, TAIMEI, TOKO, ANNAN and BUNZAN MARUs.
E 10 December 1942:
CH 39 is detached at 28N.
E 12 December 1942:
PB-46 and CH-37 are detached at 23N.
18 December 1942:
PB-46 and and minelayer YURIJIMA depart Saeki escorting the “O" convoy (No. 8 Military Movement) consisting of FUKUEI MARU No. 9, MADRAS, KAIFUKU, HORAI, ROKKOSAN, YUKI and NICHIAI MARUs.
E 19 December 1942:
The escorts are detached at 29N.
E 29 December 1942:
PB-46 joins naval tanker NARUTO off Fukajima and escorts her south.
30 December 1942:
PB-46 is detached 90 degrees off Toi Misaki.
Enters Kure Navy Yard for repairs.
14 February 1943:
A fire breaks out at Kure Navy Yard, causing damage to PB-46 and torpedo boat HATO.
15 February 1943:
Reserve LT Yamazaki Minoru is appointed CO.
24 February 1943:
Departs Kure and arrives at Saiki.
25 February 1943:
Departs Saiki and patrols the Bungo Suido with CH-37.
28 February 1943:
PB-46 and CH-37 arrive back at Saiki.
2 March 1943:
PB-46 and subchaser CH-36 depart Saiki and join cargo transport KAGI MARU off Fukajima and escorts her south.
E 3 March 1943:
The escorts are detached 90 degrees off Toi Misaki.
4 March 1943:
Departs Sukumo and later arrives at Aburatsu.
5 March 1943:
PB 46 departs Aburatsu and arrives at Saiki before the ship and minelayer NASAMI departs Saiki escorting the “F2” convoy (No. 8 Military Movement) consisting of YOSHIDA MARU No. 3, KIYO and SATSUMA MARUs.
E 7 March 1943:
The escorts are detached at 28-30N.
8 March 1943:
PB-46 and minelayer NASAMI join tanker ITSUKUSHIMA MARU at 29-33N, 132-3E and escort her to 135E.
9 March 1943:
PB-46 arrives briefly at Sukumo before departing port.
11 March 1943:
PB-46 again arrives briefly at Sukumo before departing. Then PB-46, PB-31, torpedo boat HATO, minelayer NUWAJIMA and subchaser CH-36 escort battleship HARUNA from Osumi Kaikyo to Okinoshima.
13 March 1943:
Arrives at Saiki.
14 March 1943:
PB-46 and torpedo boat HATO depart Saiki escorting the “G2” convoy (No. 8 Military Movement) consisting of TEIKAI (ex German FULDA), TSUYAMA, TAIRIN and ATLAS MARUs.
15 March 1943:
Reserve LT Fubuki Norishige is appointed CO.
16 March 1943:
The escorts are detached from the convoy at 28-30N and join IJN water tanker NIPPO MARU towing submarine I-33 escorted by destroyer YUNAGI and auxiliary gunboats CHOUN and HEIJO MARUs and head north.
E 17 March 1943:
The escorts are detached off Fukajima. Soon after PB-46 arrives at Saiki.
19 March 1943:
20 March 1943:
PB-46, minelayers NATSUSHIMA and NUWAJIMA and torpedo boat HATO escort battleship HARUNA, aircraft carriers SHOKAKU and RYUHO and their escorting destroyers to Okinoshima. Later this evening departs Sukumo and off Fukujima meets up with auxiliary submarine tender YASUKUNI MARU and starts escorting her.
21 March 1943:
At 2130 detaches and arrives at Saeki later that day.
22 March 1943:
24 March 1943:
Arrives at Saiki.
25 March 1943:
Departs Saiki with torpedo boat HATO escorting Army landing craft depot ship MAYASAN MARU.
E 26 March 1943:
PB-46 is detached at 30N.
27 March 1943:
Arrives back at Saiki.
28 March 1943:
PB-46 and minelayer YURIJIMA depart Saiki escorting the “K2” convoy (No. 8 Military Movement) consisting of YONEYAMA, SHUNSHO, and SHINTO MARUs.
E 29 March 1943:
The escort is detached at 29N.
30 March 1943:
PB-46 joins storeship IRAKO at 29-05N, 134-04E and escorts her north through the Bungo Straits.
E 31 March 1943:
PB-46 is detached off Fukajima. Later that day arrives at Saiki.
1 April 1943:
2 April 1943:
Arrives at Kure.
12 April 1943:
13 April 1943:
Arrives at Saiki. Then PB-46 and torpedo boat HATO depart Saiki escorting convoy K-413 consisting of SORACHI, HAMBURG, HIMALAYA, IKOMA, TAIFUKU and YOSHINO MARUs.
E 14 April 1943:
PB 46 is detached at 29N.
15 April 1943:
PB-46 arrives back at Saiki.
20 April 1943:
At 0600, PB-46 and minelayer YURIJIMA depart Saeki escorting convoy No. 420 consisting of ONOE, KINKASAN, and KOYU MARUs.
E 21 April 1943:
YURIJIMA is detached at 29N.
28 April 1943:
At 1440, arrives at Palau.
2 May 1943:
At 0650, departs Palau escorting convoy No. P-502 consisting of MITAKESAN, MYOKO, MUKO, NISSHO, SHICHISEI, FUKUYAMA and MYOGI MARUs.
9 May 1943:
About noon, auxiliary minesweeper TAKUNAN MARU No. 3 joins the escort.
10 May 1943:
At 1145, arrives at Saiki.
11 May 1943:
Departs Saiki but soon after returns to Saiki.
13 May 1943:
14 May 1943:
PB-46 joins IJA landing craft depot ship NIGITSU MARU at 27-27N, 134-05E and escorts her north.
E 16 May 1943:
PB-46 is detached off Fukajima and later arrives at Saiki.
17 May 1943:
18 May 1943:
PB-46 joins tanker KOKUYO MARU at 30-38N, 131-46E and escorts her to Saiki.
24 May 1943:
Departs Saeki escorting IJA Landing craft depot ship NIGITSU MARU south.
25 May 1943:
PB-46 is detached at 29N and returns briefly to Saiki. She then departs and joins seaplane carrier NISSHIN off Fukajima and, with two unidentified auxiliary subchasers, escorts her south.
E 27 May 1943:
PB-46 and the auxiliary subchasers are detached off Ashizuri Zaki. PB-46 and minesweeper W-31 join convoy P-523 at 29 -50N, 132-02E consisting of TEIRYU (ex German AUGSBURG), CHINZEI, FUKKO, TOYO, KACHOSAN and ARATAMA MARUs being escorted by minelayer NUWAJIMA.
30 May 1943:
Arrives at Furue.
2 June 1943:
At 0800, PB-46 and minesweeper W-18 depart Saiki escorting convoy O-204 for Palau consisting of GENOA, SEIZAN, SHICHISEI and KEIZAN MARUs.
E 3 June 1943:
W-18 is detached at 29N.
11 June 1943:
NW of Palau. At about 0950, in squall conditions, LtCdr (later Vice Admiral) John A. Tyree’s (USNA ’33) USS FINBACK (SS-230) attacks the convoy. Tyree fires three torpedoes and gets at least one hit in GENOA MARU’s forward in No. 1 hold. PB-46 counterattacks, but fails to inflict damage, and FINBACK escapes. GENOA MARU continues to progressively flood forward until 1730, when Abandon Ship is ordered. At 1851, she sinks by the bow at 07-35N, 134-28E. The ship was loaded with 9300 cartons of foodstuffs, clothes, weapons and two passengers, one of whom was killed. At 1158, the remainder of convoy O-204 arrives at Palau.
19 June 1943:
At 0545, departs Palau in convoy To-906 consisting of DELAGOA, DAINICHI, KAZAN, MACASSAR, SAN FRANCISCO MARUs and EIKO MARU No. 2, escorted by PB-46 and minesweeper W-17.
E 20 June 1943:
At latitude 10N, W-17 is detached and returns to Palau.
E 27 June 1943:
Minelayers YURIJIMA and NUWAJIMA join as additional escorts at 30-40N 134-50E,
28 June 1943:
At 1920, arrives at Saiki.
5 July 1943:
Departs Kure and later that day arrives at Saiki.
8 July 1943:
PB-46, minesweeper W-18 and auxiliary gunboat HINO MARU No. 5 depart Saiki escorting convoy O-806 convoy consisting of fleet supply ship ARASAKI and ASO, EHIME, KAZAN and ZUISHO MARUs bound for Palau.
E 9 July 1943:
W-18 is detached at 29N.
16 July 1943:
At 1200, the convoy, except straggler KAZAN MARU, arrives at Palau.
17 July 1943:
PB-46, presumably escorting KAZAN MARU, arrives at Palau.
20 July 1943:
At 1200, PB-46 departs Palau with minesweeper W-17 escorting convoy FU-006 consisting of ERIE, KINKASAN, KENZAN, NISSHU, KAMO and INARI MARUs.
E 21 July 1943:
At 10N, W-17 and probably PB-46 are detached to return to Palau.
24 July 1943:
Arrives at Palau.
25 July 1943:
At 1345, PB-46 departs Palau escorting convoy FU-506 consisting of MATSUE (SHOKO), HIBI, KOYO, YURI, KOFUKU and MUKO MARUs.
E 31 July 1943:
Minelayer YURIJIMA and auxiliary minesweeper TAKUNAN MARU No. 3 join the convoy at 28-25N, 136-40E.
2 August 1943:
At 1800, arrives at Saiki.
3 August 1943:
Departs Saiki and later arrives at Kure.
11 August 1943:
Departs Kure and later that day arrives at Saiki.
12 August 1943:
At 0730, PB-46 departs Saiki for Palau with subchaser CH-11, auxiliary minesweepers TAMA MARU and TAKUNAN MARU No. 3 escorting convoy O-208 consisting of HIBI, MATSUE (SHOKO), YASUKUNI, MOJI, FUKKAI, YASUSHIMA, SHICHISEI and UMEKAWA MARUs. At latitude 29N, TAKUNAN MARU and TAMA MARU No. 3 are detached to return to Saeki.
21 August 1943:
At 1320, arrives at Palau.
24 August 1943:
At 0700, PB-46 departs Palau for Ujina with auxiliary gunboat KAZAN MARU escorting convoy FU-407 consisting of empty troop ships BRAZIL, FUKKO, HAVRE, YAMATO, TOHO and MINRYO MARUS. LtCdr (later Cdr) John A. Scott's (USNA ’28) USS TUNNY (SS-282) makes several attacks on the convoy, but is unsuccessful, probably due to defective Mark 14 torpedoes of which Scott fires 11. TUNNY is depth charged, damaged and after a fire breaks out aboard, forced to abort her war patrol.
E 2 September 1943:
Auxiliary gunboat CHOUN MARU, auxiliary netlayer TAISHU MARU, auxiliary minesweepers TAKUNAN MARU No. 3 and TAKUNAN MARU No. 8 and auxiliary patrol boats TAITON MARU and NITTO MARU No. 12 join the convoy at 29-41N, 133-16E
3 September 1943:
Arrives at Fukashima, then departs.
4 September 1943:
Arrives at Ujina.
28 September 1943:
PB-46 departs Yokosuka with destroyer UMIKAZE and auxiliary subchasers CHa-25 and CHa-27 escorting convoy No. 3928 consisting of SANSEI MARU (3266 gt) and one unidentified merchant ship.
4 October 1943:
Arrives at Chichijima.
20 October 1944:
Reserve LT Ninomiya Jinsaku is appointed CO.
14 November 1943:
At 1200, convoy No. 4114 consisting of UDO, NIKKO, CHIYO and HOKKO MARUs escorted by destroyer YUZUKI, kaibokan FUKUE and PB-46 departs Truk. HOKKO MARU is towing damaged subchaser CH-10.
19 November 1943:
NE of Asuncion Island, Northern Marianas. In the early morning hours, Cdr (MOH, posthumously) Samuel Dealey's (USNA ’30) USS HARDER (SS-257) makes radar contact off the port quarter of the convoy. Dealey attempts to contact two other boats of his wolfpack, USS PARGO (SS-264) and USS SNOOK (SS-279), but all radio frequencies are jammed by the Japanese. Dealey makes an "end-around" then submerges 15,000 yards ahead of the convoy. HARDER is detected by YUZUKI’s sonar before Dealey's crew can work out a good solution and Dealey has to snap-shoot to avoid being rammed by one of the transports. At 0415 (JST), 5,384-ton HOKKO MARU is hit. At 0435, she sinks at 22-27N, 147-15E. Of the approximately 640 passengers and troops on board, one trooper together with three crewmen are killed. Dealey swings HARDER around and fires his four stern tubes. At 0435, UDO MARU is hit and badly damaged. Five crewmen are KIA. 
YUZUKI takes UDO MARU in tow, but at 1040, the transport's hull splits and the aft part of the ship sinks. CHIYO MARU takes up towing CH-10 and heads for Chichi-Jima with FUKUE. Later, NIKKO MARU is ordered back to assist in the tow of UDO MARU. At 1850, NIKKO MARU arrives back on the scene, but experiences great difficulty trying to tow UDO MARU. Finally, the wreck is abandoned and sinks a few hours later.
The escorts counterattack and drive HARDER deep under a thermocline layer of colder water. Dealey's crew counts 64 depth depth charges dropped over the next five hours during which time they reload all tubes. HARDER surfaces early in the afternoon and takes up the chase again. That night, Dealey closes to within 1,000 yards of the convoy. He fires four Mark 14-3A steam torpedoes at a transport, but they all run deep and pass under the target. Dealey makes another end-around and submerges 12,000 yards ahead of the convoy. He sets up and at 2355, fires three bow torpedoes and gets two hits, one amidships and another in NIKKO MARU's stern.
20 November 1943:
The Japanese get all NIKKO MARU's pumps running and efficiently control the flooding. In the early morning hours, HARDER fires five more torpedoes at her, but all miss. NIKKO MARU maneuvers so that she can comb the wake before the third one is fired. The last torpedo makes a circular run, forcing HARDER to submerge to prevent her being hit.
Dealey attempts to battle-surface on NIKKO MARU, but the merchant finds the range first and straddles HARDER, forcing her down again. Out of torpedoes a frustrated Sam Dealey departs the area, but later, NIKKO MARU loses her battle with the sea and sinks. 15 crewmen have been killed.
USN codebreakers intercept and decrypt a message from the captain of Patrol Boat PB-46 that reads:“At 0900, HOKKO MARU sank in position 23-42 N, 140- (?) E.”
At 1540, USN codebreakers intercept and decrypt a message from an unknown station that says, “YUZUKI will proceed to Yokosuka and undergo repairs.”
27 November 1943:
Arrives at Yokosuka.
2 December 1943:
At 0600, PB-46 departs Chichi-Jima for Yokosuka with minesweeper W-28 escorting a convoy consisting of SANKISAN and HINODE MARUs.
4 December 1943:
Tokyo Bay. Arrives at Tateyama.
5-6 December 1943:
At 2350, departs Tateyama. Arrives at Yokosuka.
11 December 1943:
At 1000, PB-46 departs Yokosuka with kaibokan OKI and subchaser CH-31 escorting convoy No. 3211A consisting of transports MITAKESAN and HAKOZAKI MARUs and auxiliary storeship SHINYO MARU.
14 December 1943:
HAKOZAKI MARU is detached for Chichi-Jima with engine trouble. Auxiliary storeship SHINYO MARU also detaches for same destination.
20 December 1943:
At 0800, the convoy arrives at Truk.
22 December 1943:
While escorting transport HAKOZAKI MARU from Chichi-Jima, a torpedo attack occurs at 09-40N, 145-51E. In avoiding torpedoes, HAKOZAKI MARU causes PB-46 to collide with her, damaging the vessel’s bow. 
December 1943-January 1944:
Yokohama. PB-46 probably undergoes repairs to her bow.
10 January 1944:
At 0700, departs Yokohama for Owase with SAISHU MARU No. 6 and SAISHU MARU No. 7 escorting convoy No. 7110 consisting of KOGYO, MISHIMA, TAIRYU MARU and an unidentified freighter.
12 January 1944:
S of Daio Zaki, Honshu. At about 2300, LtCdr (later Rear Admiral) William B. Sieglaff's (USNA ’31) USS TAUTOG (SS-199) attacks the convoy at 34-10N, 136-55E. Sieglaff torpedoes and damages KOGYO MARU that takes on a list to port. The Ise Bay Guard Unit dispatches several subchasers to the area to intercept the submarine.
13 January 1944:
After 0003, PB-46 conducts a depth-charge attack against an underwater target, then takes KOGYO MARU under tow.
14 January 1944:
Returns to Owase Bay.
6 April 1944:
Auxiliary minelayer TAKACHIHO MARU meets up with auxiliary oil tanker MARIFU MARU and starts towing her (probably because of an engine breakdown). At 1720, patrol boat PB-46 arrives and starts monitoring the towing and starts escorting both.
7 April 1944:
TAKACHIHO MARU arrives at Toba while PB-46 heads towards Nagoya, presumably with MARIFU MARU.
20 May 1944:
PB-46 is reassigned to the Yokosuka Naval District’s 3rd Surface Escort Division.
13 June 1944:
At 0500 off Tateyama meets up with transport GOKOKU MARU and escorts ship west towards Owase. At 1410 ceases escort. Auxiliary submarine chaser MISAGO MARU No. 3 takes over escort.
10 November 1944:
SW of Cape Iro (Iro Zaki). At 0845 (I), LtCdr John D. Gerwick’s (USNA ’35) USS GREENLING (SS-213) sights a medium sized tanker escorted by what he correctly identifies as a WAKATAKE-Class destroyer crossing Suruga Bay heading west. A 0853 (I), two medium bombers are sighted over the target area.
Gerwick swings GREENLING hard left to bring his stern tubes to bear and at 0939 (I) fires four Mark-18 electric torpedoes at the "destroyer" and gets one hit that sinks PB-46 at 34-30N, 138-34E. Reserve LT Ninomiya and an unknown number of crewmen are KIA. LT Ninomiya is promoted LtCdr, posthumusly.
Japanese planes drop six bombs, but USS GREENLING escapes.
10 January 1945:
Removed from the Navy List.
 The various convoys of the No. 8 Military Movement were enroute to Saipan, Carolines.
 Some of USS HARDER's "hits" may have actually been duds.
 The unsuccessful torpedo attack probably was made by LtCdr Michael P. Russillo's USS MUSKALUNGE (SS-262).
Thanks to Mr. Gilbert Casse of France for general assistance with revision 4. Thanks also go to Matt Jones of MS and Fontessa of Japan for help with COs in Rev 6.
-Bob Hackett, Sander Kingsepp and Peter Cundall
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